The Economist - USA (2022-05-21)

TheEconomistMay21st 2022

Graphic detail Climate change

85

That non-sinking

feeling

I

f rainforestswereEarth’srespiratory

system, the Amazon would be a full lung.

The region holds half of the tropics’ undis­

turbed forests. Its flora absorb 1.5bn tonnes

of  carbon  dioxide  (CO 2 )  a  year,  equivalent

to 4% of emissions from fossil fuels.

This lung is being deforested at cancer­

ous rates. A chunk nearly the size of Kuwait

is  felled  or  burned  every  year.  This  both

eliminates CO 2 ­absorbing trees and releas­

es their stored carbon back into the air.

The  worst  scenarios  involve  a  tipping

point of tree loss, beyond which the forest

could no longer produce enough moisture

to sustain its ecosystem. But even if this di­

saster can be averted, grave harm has alrea­

dy been done to Earth’s best­known carbon

sink.  Since  2016  the  Brazilian  Amazon,

containing  two­thirds  of  the  forest,  has

spewed out more CO 2 than it has absorbed.

Two analyses from 2021 identified

chunks of theAmazon as net emitters.

One,inNature, foundthispatterninatmo­

sphericsamplesfromsouth­easternAma­

zonia.Theotherbuiltona paperinNature

ClimateChange, whichcombinedsatellite

images oftree losses withdata on soil

types; tree densities and ages; and the

emissions impact of land­use changes.

Based ontheresultingestimatesofCO 2

flows, authors at maap, a conservation

group,calculatedthatin2001­20netemis­

sionsfromtheBrazilianAmazonexceeded

thoseofArgentinaorPakistan—although

thefullAmazon,includingneighbouring

countries,remaineda netcarbonsink.

Bothofthesestudiesmeasuredemis­

sionsoverlongtimeperiods.Neitherre­

portedwhetherrecentregion­widetrends

werepositiveornegative.Tofindout,we

matchedupthelatestdataonCO 2 flows

withyearlymapsoftreecover.

CO 2 capturehasdeterioratedslowlyand

steadily.Since 2001 theBrazilianAmazon’s

absorptionratehasfallenby1.2%a year.

Emissions,incontrast,haveoscillated.

Inthemid­2000sCO 2 outputfell,asthe

centralbankcutoffcredittofirmsfacing

finesfordeforestation,andmoreforestar­

easgainedlegalprotection.Butin 2012 the

governmentgrantedanamnestyforpast

deforestation,andin 2014 a recessionbe­

gan,whichmayhavepushedfarmersto

seeknewland.Afternineyearsasa carbon

sink,emissionssurgedin2016,andthere­

gionhasbeena netemittereversince.

Brazilhaspledgedtoendillegaldefor­

estation by 2028. However, Jair Bolsonaro,

the president, has relaxed enforcement of

environmental  safeguards.  Satellite  imag­

es  suggest  that  twice  as  much  forest  has

been lost in 2022 as the average for January

to April in 2010­21. The future pathofglo­

bal  warming  depends  in  part  onwhether

Mr Bolsonaro is re­elected this year.n

The Brazilian Amazon has been a

net carbon emitter since 2016

→Deforestationleaves

a signatureinparallel

rowsofhighemissions

CruzeiroCruzeirododoSulSul

São Luís

Porto PortoVVelhoelho

RioRioBrancoBranco

BoaBoaVistaVista

Macapá

ManausManaus

MarabáMarabá

Vilhena

ColíderColíder

Cuiabá

BelBelémém

BRAZIL

BOLIVIA

PERU

COLOMBIA

VENEZUELA GUYANA

SURINAME

FRENCH

GUIANA

ATL A NTI C

OCEAN

Ama

zon

Ama

zon SantarémSantarém

-1,000

0

1,000

2,000

3,000

01234

56

Million square km

↓ A few regions with sky-high

emissions outweigh a larger

area with modest absorption

Greenhouse-gas flows,

average for 200-2

-800 -400 0 400 800

Removals Emissions

→ A surge in deforestation has turned the Brazilian Amazon into a net emitter of carbon dioxide

Greenhouse-gas flows, average for 200-2

Tonnes of CO2 equivalent per square km

Sources: “Global maps of twenty-first century forest carbon fluxes”, Harris et al.,

Nature Climate Change, 202; Hansen; UMD; Google; USGS; NASA; The Economist

Greenhouse-gas flows in the Brazilian Amazon

Tonnes of CO equivalent, bn

-1

0

1

2

2001 05 10 15 21

Emissions

Net

Removals